1. Technical Field
The present invention relates to an apparatus and method for registering the cycling of an automatic pump, and more particularly to a non-invasive apparatus and method that utilizes a magnetic sensor positioned externally to a pumping system in order to count the number of cycles of operation of an automatic pump.
2. Discussion
The ability to count the number of cycles a pump has gone through is becoming increasingly important as a result of the substantial rise in the number of identified sites of contaminated ground water. Accompanying this trend has been an increased effort to clean up these sites. In response, there is a need for improved below ground pumping systems to assist in these clean up efforts.
When taking samples of groundwater for these clean up efforts, it is first necessary to purge the water in the well or monitoring site in order to get a representative sample of the groundwater. The volume of groundwater will normally be purged 3 to 5 times prior to taking a sample of the groundwater. The purging requires a relatively large number of cycles of the pump. Thus, in order to be able to effectively and consistently retrieve acceptable groundwater samples, a person must accurately know the number of cycles the pump has gone through.
Previous designs used to determine when a pump has cycled utilize sensing technology that senses the flow of air in the pump. Specifically, these designs utilize a diaphragm type sensing element in junction with either a variable orifice or a flow switch to detect the pulse of air into or out of an air displacement pump. While effective in many applications, it is still possible that the diaphragm might miss the air pulse if the variable orifice is not adjusted properly or if the pneumatic lines leading to the pump are excessively long. If transient conditions such as either air hammer, pressure spikes due to valves opening or closing, or other phenomena occur, these designs may also actuate repeatedly when no actuation should occur. Both designs affect pump performance because they place restrictions in the air supply line to the pump. Additionally, they are invasive techniques that require more maintenance, and hence are more expensive. Furthermore, these designs only detect the symptom of the pump entering the discharge phase of the pump cycle, which is the air pulse associated with the pump being in this phase.
Accordingly, what is needed is an apparatus which can sense the direct cause of the pump cycling, namely the change of position of internal parts which repeatedly move along a fixed path in response to a cycle of fluid flow.
While the present invention is being described for exemplary purposes utilized with a pumping system which is capable of self-activating in response to surrounding liquid levels, it is to be understood that the present invention can be utilized for counting cycles with any type of pump that has a part which moves in response to a cycle of fluid flow.